This invaluable book provides the first description of the diverse and fascinating functions of heme in life processes for a broad audience. It begins with an introduction to the intricate chemical properties of heme and the history of early observations of human diseases associated with heme. It then proceeds to describe the versatile roles of heme in controlling diverse molecular and cellular processes germane to human life and disease processes. Finally, an up-to-date review of human diseases associated with heme synthesis and application of heme synthesis in photodynamic therapy in cancer treatment is presented.Heme biology is unified and logical in presentation. It is well suited for students and professionals in life sciences who wish to comprehend the fascinating biology of heme and its usefulness in health and diseases. It may also be used as a reference book for advanced readers and researchers who are interested in heme biology. The explanations in the book are detailed eugh to capture the interest of the curious reader, and complete eugh to provide the necessary information for researchers to have an in-depth molecular understanding of heme biology and further their studies in this fascinating realm.